The present invention relates generally to a utility access, such as a manhole. More particularly the present invention relates to a height adjustable utility access or manhole having a variable cover height adjustment to allow the top of the cover to sit flush with the surrounding surface, such as a road.
A manhole is an opening in any surface large enough to allow workmen to descend beneath the surface to obtain access to stored materials or equipment or underground installations. The openings are normally in areas carrying traffic so that a means of securely framing and covering the opening must be provided. The manholes must also be strong enough to withstand various external loadings, for example the loading of vehicles moving over the manhole.
In the prior art, the standard procedure has been to frame the opening with a grey iron casting. For example, Dand L Supply, of 880 West 150 North, in Lindon, Utah 84042, sells various styles of manhole assemblies. These castings typically incorporate a flanged surface that rests on a supporting structure that is located underground. This supporting structure typically comprises of standard concrete rings long enough so that a number of them form a passage to reach the underground installation. The flanged surface of the manhole transmits the weight of the equipment, together with live surface loads, to the supporting structure. The frame typically incorporates a projecting ledge around the circumference and a cast iron cover rests on the ledge and closes the manhole. The cover is a removable casting designed to carry the surface loads, and must transmit those forces to the underground supporting structure through the frame. The cover must be heavy to avoid vandalism. In some cases it is bolted down in order to make the installation water tight and tamper proof.
In one situation, a subsequent layer of surfacing material (for example, asphalt) is added to the road surface. When this happens, the manhole may need to be adjusted to match the height of the new road. Typically, adjustment is done by filling the space between the manhole top structure and the supporting manhole frame structure with layers of bricks and mortar. This is a manual, time-consuming procedure. In addition, spacers may be used.
Examples of patents related to the present invention, each of which are incorporated herein by reference for their supporting teachings, are as follows:
One patent which illustrates an adjustable manhole is U.S. Pat. No. 4,273,467 to Cronk. The device designed by Cronk is an adjustable manhole cover support. The support comprises of an outer ring having a circular internal opening. Threaded members are disposed about the interior of the circular opening. An insert is dimensioned to fit within the outer ring to a depth controlled by the abutment of the insert against the threaded members. Studs engage and extend through the threaded members to abut the under surface of the insert to provide control of the depth of the insert into the outer ring and the angulation of the outer ring. The support is simple to make, easy to adjust and trouble-free in operation.
U.S. Pat. No. 5,496,128, is an internal fastening band for an internal manhole chimney seal, as well as a means for expanding the band and a means for removing the band. One end of the band is narrower than the other end so that when overlapped the ends of the band nest into one another to form a continuous expansion band. The first end portion has a plurality of apertures longitudinally spaced along the fastening band, and a plurality of slots spaced between the apertures at the end of the fastening band. The second end portion also has an aperture along a tab for engaging one of the slots to connect the first end portion to the second end portion with the particular slot being selected to adjust the continuous circular fastening band to a desired diameter. A tool is described for engaging an aperture in each end portion to increase the diameter of the circular expansion band and force the resilient sleeve against the inside surface of the manhole. An attachment for this tool enabling the removal of this band is also disclosed.
A further related U.S. Pat. No. is 5,564,855, which discloses a stackable height adjustment ring for supporting a manhole cover frame upon a concrete manhole shaft liner that has a ring body that is formed from plastic resin. The ring includes inner and outer radially spaced apart side walls, and optionally, a top wall. Brace arms that are integral with the walls preferably extend radially between the walls for holding them together. The rings have alignment members, e.g., an inner wall of tiering may have an upwardly facing shoulder upon its upper edge and the outer wall, a downwardly facing shoulder on its lower edge. An upwardly extending cylindrical collar at the top of the outer ring fits the downwardly facing shoulder of an adjacent ring. There is also a downwardly extending collar at the lower end of the inner ring to fit on the upwardly facing shoulder of a similar inner ring. The alignment members enable each ring to be held in alignment upon each successive ring beneath it so that the rings can be stacked one upon another to adjust the elevation of the manhole cover frame above a concrete manhole shaft liner. Optionally, the rings have engageable ramps for adjusting the pitch of an upper one of two stacked rings.
A similar U.S. Pat. No. 5,956,905, is a molded plastic extension member for use in increasing the height of manholes, or catch basins when surfacing or resurfacing a roadway. The extension member may be formed having a sloping upper planar support surface to thereby adjust the angle of the catch basin support frame or the manhole cover support frame. An outer surface of the extension member includes indicia that allows the user to align the slope of the upper planer support frame. An outer surface of the extension member includes indicia that allows the user to align the slope of the upper planar support surface parallel with the roadway surface. When several sloped extension members are stacked, the indicia may be used to create a complex angle of slope relative to the underlying base members vertical axis. The extension member includes a pocket adaptable for receiving and retaining mortar between two stacked extensions. Planar surfaces may extend from both the upper and lower edge of the extension member, thereby providing support and added stacking surface for the stacked extension members. The extension member also includes a tapered shoulder that interlocks with either the manhole cone, the catch-basin cone, or with other stackable angled plastic members.
Yet a further prior art U.S. Pat. No. 4,337,005, is concerned with an apparatus for enabling extension or other leveling adjustment of manhole cover supporting structures and the like comprising extension spacer rings resiliently compressed in self-storing fashion adjacent a support sleeve portion of the supporting structure, and adapted to be faced downward from storage to expand into position below the sleeve to extend or adjust the level of the same.
Another manhole cover U.S. Pat. No. 5,366,317, includes a collar defining an opening with an inner perimeter is provided with a pivotally mounted cover having an outer perimeter greater than the inner perimeter of the collar. A seal is provided to seal between the cover and the collar. Closure structure is provided to secure the free end of the cover to the collar. A threaded bolt is provided to close the cover. A pivotally mounted lever arm is mounted to the bolt for turning of the bolt. An adjustable threaded hinge is provided to adjust the cover in a longitudinal direction relative to the collar. The manhole cover apparatus is useable on pressure containers, such as those used to pneumatically handle particulate material.
U.S. Pat. No. 5,451,119, is a barrel-shaped manhole frame for receiving a manhole cover is provided with an inwardly directed peripheral flange at its lower end having circumferentially spaced, inclined grooves to receive wedges that can be driven into surrounding earthwork to wedge the frame upwardly and thereby adjust its height and slope to conform with a roadway or sidewall surface under construction.
Additionally, U.S. Pat. No. 5,470,172, is a molded plastic extension member for use in increasing the height of manholes, or catch basins when surfacing or resurfacing a roadway is described. A wedge to adjust the angle of the catch basin support frame or the manhole cover support frame is also described. The extension includes a pocket for reducing the total surface area of the molded plastic member. It also includes a shoulder that interlocks with either the manhole cone, the catch basin cone, or with other stackable molded plastic members. The extension also contains a planer support surface which provides rigidity and support, and provides a surface for caulking to be applied to form a watertight seal.
It has been recognized that it would be advantageous to develop an improved utility access or manhole top structure which is adjustable in height. In addition, it has been recognized that it would be advantageous to develop a utility access or manhole with a variable cover height adjustment to allow the top of the cover to sit flush with the surrounding surface, such as a road.
The invention provides a height adjustable utility access device with a height adjustment means for adjusting the height of a cover relative to a frame. Thus, the cover can be positioned flush with a surface, such as a roadway. The utility access can be a manhole.
The frame can be secured to a support surface over a utility, such as a manhole extension. The frame has an opening therethrough to provide access to the utility. The cover is removably disposed over the opening of the frame. The height adjustment means is disposed between the frame and the cover.
The height adjustment means can include a first position that maintains the cover at a first height, and a different second position that maintains the cover at a different second height. The height adjustment means can include a plurality of positions for a plurality of heights.
In accordance with one aspect of the present invention, the height adjustment means can include a plurality of steps or pockets formed about a circumference of the opening. The steps can be disposed at different elevations, or the pockets can have bottoms disposed at different elevations. At least one mating tab selectively mates or engages with at least one of the steps or pockets, to selectively position the tab, and thus the cover, at a desired elevation or height.
In accordance with another aspect of the present invention, the height adjustment means can include an extension or extension ring disposed on the frame. The extension ring can have the least one tab formed thereon.
In accordance with another aspect of the present invention, the plurality of steps or pockets can be formed in an adaptor or adaptor ring. The adaptor ring can be disposed on the frame and receive the extension ring. Thus, the height adjustment means can be used with a standard frame. Alternatively, the plurality of steps or pockets can be formed directly in the frame, with the frame receiving the extension ring.
In accordance with another aspect of the present invention, the plurality of steps or pockets can include a wall disposed between a step and a proximal step, to prevent the tab from inadvertently moving from the step to the proximal step.
In accordance with another aspect of the present invention, the height adjustment means can include a pair of rings disposed between the frame and the cover. A first ring is disposed on the frame and has a plurality of steps at different elevations. A second ring is disposed on the first ring and has a plurality of steps at different elevations. The plurality of steps of the first and second rings selectively engage to selectively elevate the second ring with respect to the first ring.
In accordance with another aspect of the present invention, the device can include at least one projection extending outwardly from the frame and past a perimeter thereof. The protrusion can resist movement or pivoting of the frame after installation.
Additional features and advantages of the invention will be set forth in the detailed description which follows, taken in conjunction with the accompanying drawings, which together illustrate by way of example, the features of the invention.